Public Outreach: Take Astronomy to the Public

International Astronomy Day

Every year in late April or early May Astronomy organizations around the world stage public exhibitions on Astronomy. The event is coordinated by the Astronomical League, and the date is chosen to be a weekend with good observing conditions — a Saturday near or just before the 1st quarter moon (there is also an alternate “rain date” in September).

People in RASC participates as do other local Astronomy clubs. There will be exhibits at the museum and in other public places, and usually one or more evening star parties organized for easy public accessibility. Watch for announcements in our news letters and on our web site.

Public Outreach

Astronomy Day is one example of Public Outreach, but Outreach can be done at any time, with or without the formal structure of Astronomy Day. And it’s extremely rewarding — for many of us it is a major part of the hobby. Personally, I love it and prefer it to any other aspect of our hobby.

If you haven’t participated in a public outreach session, you should try it. You may find you’ve been missing a great experience.


Outreach events are a good rallying point for astronomy groups, and are a centre point of the activities of all the Ottawa clubs. Public outreach is also good for the hobby of amateur Astronomy, as it brings new entrants into the field, raises public awareness of light pollution, and helps raise the general public awareness of this science, and Science in general.

Frankly, my love of outreach is, however, more selfish. I enjoy reliving my first good views through a telescope by giving others that opportunity. Hearing “oh my god!”, and “I can’t believe it!”, and countless other expletives, dozens of times in an evening is something I never tire of.

This article is to encourage members who have never joined an outreach event to do so. It is well worth the small effort, and can become a very rewarding aspect of the hobby.


Outreach events can be held almost anywhere. It is worth thinking about this for a while because outreach often involves locations we wouldn’t normally consider as good sites for observing. This is because of a simple fact of outreach Astronomy:

The better the observing conditions, the harder it is for the public to attend.

On the other hand,

The easier it is to attend, the less there is to observe.

To avoid disappointing yourself or your guests, it helps to think about this in a structured way.

It suggests there are different kinds of outreach events. If you want to show Saturn to a huge number of people, you need to do this where the people are, in the city; and then you should not waste your time and theirs trying to find a dim galaxy. To look at dim galaxies you need to travel to a dark site, and then you shouldn’t expect large numbers to show up; and if they do they won’t know “star party rules”, and they’ll come in with headlights and flashlights.

We might divide events into three broad classes based on sky quality and ease of access:

True dark sky
At these events the emphasis is on observing conditions, not convenience, and the audience is mainly astronomers and their personal acquaintances. Star Party rules apply, and it’s OK to expect people to know about turning their lights off.
Accessible, reasonably good sky
These events offer “the darkest sky and best horizon that is still easily accessible by non-fanatics”. Your guests will have to decide to visit this event — it’s not on their way somewhere — but it’s easy to do. What makes a site easily accessible for people who want a taste of Astronomy?

  • In the city or on the outskirts; not far
  • Good roads to get there, paved all the way or except for the last few metres
  • Safe parking
  • Washrooms
  • Not scary — minimal fear of being eaten by a bear, shot by a hunter, or falling off a cliff
  • Bugs not too bad

A good example of such a site is the Carp Library at the Diefenbunker.

These events will be announced in advance, will likely have rain dates, and will likely have someone coordinating them. Remember these events are for the public — there will be flashlights, headlights, and dogs.

Sidewalk Astronomy
At the opposite end of the scale from dark sky parties is sidewalk astronomy — a term originally coined by John Dobson (yes, that Dobson). The motto of sidewalk astronomers is Bringing Astronomy to the Public. These events are set up with accessibility as the #1 priority. You set up somewhere the public will be anyway — shopping malls, parks, community events, etc. — so they don’t have to make a decision to come. Attributes of a good Sidewalk site include:

  • Parking for astronomers and a place to set up;
  • Not more than about 10 metres from a major flow of pedestrian traffic;
  • Southern sky exposure, so moon and bright planets are visible on the ecliptic;
  • Appropriate approvals and permissions of landowners. Because such locations are usually brightly lit, observing conditions are usually terrible, permitting only very bright objects to be seen. But that doesn’t matter — showing someone their first view of Saturn is enough.

All the Ottawa astronomy groups host star parties, with Sidewalk astronomy being the specialty of OAOG, and OAFs. There tend to be one or two events per month during the season when there are interesting objects to show. RASC Ottawa Centre events tend to focus on the middle, “reasonably accessible, reasonably good sky”, category. Check all these groups’ web sites for information on their event plans and locations.

Outreach events are very satisfying and, as an amateur astronomer, you do not need sophisticated equipment or deep expertise to take part. If you haven’t joined one of these events, you should certainly try it.


The timing of outreach events tends to be different depending on the type. Serious and semi-serious events prefer to avoid the moon, while sidewalk astronomy events are best when the moon is visible, anywhere from a thin crescent to nearly full. The novice public, especially kids, love to look at the moon, and you can’t see the very dim objects with which it interferes from a bright parking lot anyway.

For sidewalk astronomy, given the poor, light-polluted observing conditions, events need to be scheduled when there are interesting objects to show — at least the moon and one bright planet. You also want mild, stable weather so people are likely to be outside and not rushing to the warmth of their car.

Finally, it is not necessary, but it helps if there is some special astronomical event going on at the same time. An eclipse, the closest pass of Saturn, etc. The special event can be a conversation starter, and the passing public seems less suspicious of astronomers on the sidewalk if there is some plausible reason to be there other than “for fun”.

During seasons when the weather is pleasant, there will only be a couple of hours between dark and when the stores close or the parks vacate, so plan to set up before dark and be done by 11:00 or thereabouts.


Prefer a Group

You should try to do outreach in a group when possible. You’ll have better safety and security, be better able to handle crowds, and be able to take breaks while having someone tend your valuable equipment. Join an existing group when possible, especially for your first outings, to get their experience, and to ensure you are at a location that is expecting you and grants permission.

Another good approach is to do a small demonstration for an existing group with their own charter, location, permission, and supervision, such as a school science class, a boy scout or girl guide group, a camp, etc.

Choose Suitable Targets

Target objects for public outreach should be bright, known objects that are easy to find. Your guests want to look at objects, not watch you looking for objects. I also prefer objects whose visual appearance matches their photographic appearance (e.g. bright planets, star clusters, and bright nebulae) rather than galaxies. Your guests will have seen Hubble or National Geographic photos of deep space objects and are not expecting to strain to see “faint fuzzies” in the eyepiece.

Excellent objects include:

  • The moon, especially near a quarter when there are good shadows;
  • aturn, Jupiter, and, when it is close, Mars;
  • Bright clusters, especially bright globulars such as M13;
  • Bright nebula, especially ones with an interesting structure (M27, M57) or an interesting story (M1);
  • Interesting multiple stars (visually interesting, such as contrasting colours or sizes, not technically interesting, such as difficulty to split);
  • Galaxies if your scope and the sky make them visible as more than faint fuzzies, and without “averted imagination”.

At events with several telescopes, it is an excellent idea to combine several nearby scopes into a theme of some kind. Examples could include:

  • Life cycle of stars: show an emission nebula (nursery), a cluster, a planetary nebula, and a supernova remnant;
  • Several magnifications of the same object, such as the moon;
  • The same object with different kinds of telescopes, to show their capabilities.

Remembering that your guests want to observe, not watch, plan a small number of targets in advance, and switch seldom.


Obviously your optical equipment is important. Remember that the public may not have ever seen any object through any telescope, so don’t hesitate to participate no matter what equipment you have. Some thoughts to consider include:

Telescope and Mount: If possible, plan to minimize operator intervention. A driven mount that tracks objects will allow more people to observe without you having to constantly insert yourself to re-aim. If you are using a non-driven mount, you might plan to show wider-field views with longer focal-length eyepieces so you have to adjust the aim less often. Groups are best if they include a variety of types of telescopes, especially if they also include some “good entry-level” scopes to allow the public to see what they can get for a reasonable investment.

I also prefer to use eyepieces with a long eye relief so that I can focus for corrected vision (i.e. wearing my contact lenses) and visitors with and without glasses can then observe without re-focusing.

Observing Aides: If you are planning to show the moon, you might consider a neutral-density filter so the bright moon doesn’t ruin your visitors’ night vision for other objects. If you are planning to show nebulae, appropriate narrowband filters are a great help.

It is also essential that you consider your eyepiece height. Many of your visitors will be small children. If your eyepiece is not reachable by an 8-year-old, bring a step stool; preferably with side handles so they steady themselves by holding the stool, not the ‘scope.

Accessories: A number of other small accessories can make your experience more enjoyable:

  • A small table (or the flat top of your storage case) is very handy to keep parts organized.
  • At medium-sky events, a laser pointer is great for giving sky tours. (At sidewalk events it won’t be visible, and at serious dark-sky events it may be unwelcome.) Don’t let kids play with it: they wil’l point it at each other.
  • A planisphere or basic star chart (to help converse with a visitor, not to search for obscure objects) can make your demonstration more interesting and educational.
  • Old astronomy magazines, given away for free, are a real treat for your visitors, and allow you to recycle.


Getting ready for an outreach event is different than preparing for a personal observing session. You will be out for a shorter time, and your objective is sharing, not observing. Some suggestions include:

Learn your targets: Look up interesting statistics on the targets you are most likely to show. Which planet’s satellites are where? How far away is that planet, moon, or nebula? What is the name of that prominent lunar crater near the terminator? Is the Apollo landing site easy to find tonight? etc. Having some facts like these ready makes you ready for questions, and makes the experience more memorable for your guests.

Prepare your equipment: Have a checklist of all the critical parts you need. Charge or replace batteries you depend on. Make sure your red flashlight is working. Charge your cellular telephone and take along phone numbers of emergency contacts.

Prepare for, and welcome, questions: Certain questions are very common:

  • Why are you doing this? (Especially at Sidewalk events)
  • What does this equipment cost? (Tell them, but also tell them how little it can cost to begin)
  • How far away / how big is that object? (Know)
  • Fringe science and pseudoscience: astrology, etc. (Politely and gently explain the difference between science and superstition.)
  • I have a telescope too. I paid almost $40 for it a SuperWonderMart and it says “675 power” on the box. Is it any good? (Be polite; any observing is better than no observing; but set expectations)

Prepare for problems: I find certain problems are quite common:

  • First-time telescope users often cannot find the light cone of the eyepiece in the dark. Show them where to put their eye, and explain the importance of looking straight into the eyepiece. The red flashlight can help — shine it on the eyepiece until they find it, or into the end of the scope (at an angle) so they can hunt for the red light at the eyepiece. (Do this only with a dim red light — not a bright one, and not a laser!) With an object like Saturn, you’ll know when they have found it.
  • Kids will sometimes grab and pull the telescope to steady themselves, or to get the eyepiece closer, destroying your aim. Patiently re-aim, and have them hold the handles of your step stool, or their parent’s arm. I bring my sturdiest mounts to outreach sessions for exactly this reason.

Make it Interesting

You will have a variety of discussions with your visitors at the eyepiece. Some of the questions will surprise you, but others are very common and you’ll enjoy your session even more if you have some answers prepared.

Learn some of the common statistics about the objects you plan to show. How far away is it? How big is it? Have we visited it? etc.

Look up the data but, even better, learn some vivid metaphors to help your guests understand. For example, if you’re showing Saturn, it is good to know that it is 1.3 billion kilometres away, and 120,000 kilometres in diameter. But those numbers are so large that they may not mean anything to your visitor. Instead, you might offer that it is “three thousand times farther away than the moon” and that “you could line up nine Earths across the disk”. M42 is 1600 light-years away; who understands that? You could try “the space shuttle orbits at about 30,000 km/h. At that speed it would take 60 million years to get to M42. If the dinosaurs had launched a shuttle, it would be arriving at M42 around now.”

Resist spewing intimidating technical talk — you are trying to attract people to this hobby, not convince them they can’t understand it.

Here are a few useful figures and comparisons (although you may connect to them better if you work out your own):

Object Diameter Distance Diameter Example Distance Example
Moon 3,500 km 380,000 km 1/4 Earth Fly around the Earth 10 times
Venus 12,000 180 million km Almost exactly Earth 500 times farther than the moon
Mars 6,800 km 285 million km 1/2 Earth 750 times farther than the moon
Jupiter 142,800 700 million km 11 Earth diameters 1,800 times farther than the moon
Saturn 120,000 km 1.3 billion km 9 Earth diameters 3,400 times farther than the moon
Sun 1.3 million km 150 million km 100 Earth diameters 400 times farther than the moon
M42 300 trillion km (12 zeros) 15 quadrillion km 9,500 times our solar system 60 million years in the Shuttle (at 28,000 km/hr)
M13 1.4 quadrillion km (15 zeros) 240 quadrillion km 4,500 times our solar system 960 million years in the Shuttle
M31 1.3 quintillion km (18 zeros) 27 quintillion km 44 million times our solar system 100 billion years in the shuttle (8 times longer than the age of the universe)

(The planet distances in this table will obviously change with time. For the planets I like to show (Saturn and Jupiter) they don’t change very quickly, so I usually update my table about once a year. )

The other very common questions will be related to how to enter the hobby. How do you learn? What does the equipment cost? What should you buy? etc. Have some standard advice on hand (a good book, a good beginner store, a club you recommend), and have a pencil handy so your visitor can write things down. More organized events might like to prepare a handout.

Remember to advise your guest on what equipment would be good for them, not what you would like. 150 mm6 inch dobs, 100 mm4 inch refractors, etc., are good beginner scopes. The monster-sized 900 mm36-inch Obsession you would like to have is not.

Keep a Journal

If you come to love sidewalk astronomy you will soon have so many memories that they will become confused. Keep a simple journal of what you showed, how many people attended, what you learned, and any particularly memorable exclamations.

Some of the favourite memories in my sidewalk journal include:

  • Several of us decided on an impromptu sidewalk session in front of Chapters tonight. What we didn’t know was that this was also the eve of the launch of the new Harry Potter book. The store was open past midnight (since the books went on sale at midnight) and the sidewalk was packed with kids, youths, and adults, many dressed in wizard costume. What could have been better than to have Moon and Jupiter observing for the people in line? Everyone thought it was a planned part of the launch.
  • We often hear “I can’t believe it’s real”, or “it looks fake”. Tonight we had a gentleman who, I think, honestly believed that. He was convinced it was some kind of scam, that we were faking the images, and that we were eventually going to ask him for money, to buy comet insurance, or to join a cult. He kept coming back and sneaking looks into the objective end of the scopes and at the attached electronic gear, hoping to catch us in the deception.
  • A group of teens came tonight, dressed in the current punk/gangsta fashions. As usual with groups of this age, they were very careful to be “cool”, not seeming too interested, wisecracking, etc. Then one of the girls, looking at Jupiter, named the Galilean moons in order. Her friends and I both looked at her in shock. She shrugged and said, “didn’t you know I’m really a geek?” to her friends. The barriers came down, and they all looked again, asked questions, and discussed what they knew — which turned out to be quite a bit.

Public outreach is good for Astronomy, good for the public, and good for you. And it’s great fun. If you haven’t tried participating in one of these events, you should try; and Astronomy Day in April is a perfect opportunity. Join one of the exhibits happening around the city and have fun. If you missed Astronomy day, join one of the events hosted by RASC, OAOG, or OAFs, or arrange your own; but give it a try.

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